1. Field of the Invention
The invention relates to a wireless receiver module, more particularly to a pluggable external wireless receiver module for a sewing machine.
2. Description of the Related Art
Control of an internal motor of a conventional sewing machine is usually conducted through a pedal-type controller. In particular, the rotation speed of an internal motor of the sewing machine is varied according to treading action on a pedal of the controller.
Referring to FIG. 1, a conventional sewing machine is shown to include a machine body 91 having a motor (not shown) disposed therein, a socket connector 92 mounted on and accessible externally of the machine body 91, a plug connector 93 for mating with the socket connector 92, a power cord 94 and a signal cord 95 each connected at one end to the plug connector 93, and a controller 96 connected to the other end of the signal cord 95.
In operation, the controller 96 converts user treading action into corresponding control signals that are transmitted through the signal cord 95 and the socket connector 92 into the machine body 91 for controlling operation of the motor inside the machine body 91.
When the conventional sewing machine is in use, the machine body 91 is usually placed on top of a table, whereas the controller 96 is placed on the ground to permit treading on the same. Therefore, since signal transmission between the controller 96 and the machine body 91 is conducted in a wired manner, the signal cord 95 must extend from the top of the table to the ground, which can result in some inconvenience.
To overcome the aforesaid drawback, it has been proposed heretofore to use a wireless mode of transmission between the controller and the machine body. To this end, a transmitter and a receiver are respectively provided in the controller and the machine body such that the controller converts user treading action into wireless control signals for subsequent transmission by the transmitter to the receiver in the machine body, thereby permitting control of the operation of the motor in the machine body.
It is noted that the space in the machine body of a conventional sewing machine is fully utilized. Hence, installation of the receiver inside the machine body is not allowed unless the original design of the machine body is modified. In other words, it is not possible to upgrade older sewing machines for wireless transmission purposes in view of lack of sufficient space in the machine body for accommodating the receiver.